Getter holder



April '14, 1959 J. J. B. FRANSEN 2,881,909

- GETTER HOLDER Filed oct. '7. 1957 IN VEN TOR. JJN Jamasmumvsmm BY W@JTJJ AGEN.

United States Patent O GETTER HOLDER Jan Josephus Bernardus Fransen,Eindhoven, Netherlands, assignor to North American Philips Company,Inc., New York, N.Y., a corporation of Delaware Application October 7,1957, Serial No. 688,679

Claims priority, application Netherlands November 27, 1956 3 Claims.(Cl. 206-.4)

The invention relates to a tubular container for a gas binder (getter),out of which container the active substance can escape through alongitudinal opening in the envelope during the evaporation. Theinvention furthermore relates to an electric discharge tube comprisingsuch a container.

In general, such containers consist of a cylindrical envelope containingthe gas binder, for example an alloy of barium and strontium oraluminium. The envelope is cut from a long tube and, as a rule, Weldedto a U- shaped strap to permit high-frequency heating. The envelope hasa longitudinal slit, obtained for example by local grinding, from whichthe gas binder can escape during the evaporation. In a furtherembodiment the cylindrical envelope has a longitudinal groove whichbursts open during the evaporation of the gas binder. The escapingvapour constitutes a directional jet and is thus precipitated on afairly sharply limited part of the bulb of the vessel, which is ingeneral an electric discharge tube, in which the container is housed. Asharp limitation of the precipitated mirror is particularly importantwith discharge tubes having a plurality Iof electrodes and smalldimensions, since the mirror on the bulb has a particular capacityrelative to the electrodes and since it is desirable for this capacityto be the same for all tubes of the same type.

It has been found, however, that the size of the surface of the mirrormay exhibit considerable dilferences, which are found to be due tovapour of a gas binder escaping at the ends of the tubular container ina direction approximately at right angles to that of the vapor jetescaping from the longitudinal slot. Since the ends of the tubularcontiner are more or less shut by the cutting and welding operations tofasten it to the strap, the quantity of vapour escaping at these ends isnot always the same, so that an unequal extension of the mirror isoccasioned on the bulb in different tubes.

The said disadvantages can be completely obviated, if the tubularcontainer for the gas binder is slightly bent in a manner such that agas binder escaping at the ends has substantially the same direction asthe vapour of the gas binder escaping from the longitudinal slot. Thetubular container is preferably bent in a manner such that itconstitutes parts of a circle, the longitudinal slot lying on the hollowside. The container may, as an alternative, be bent in the form of a U,the longitudinal slot lying also in this case on the concave side. Atany rate care must be taken that, when the gas binder in an electricdischarge tube is evaporated, the vapour escaping at the ends of thecontainer is precipitated on the same part of the bulb as the vapourescaping from the longitudinal s ot.

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The invention will be described more fully with reference to a drawingin which:

Fig. 1 shows a discharge tube, in which a conventional straightcontainer is housed and Fig. 2 shows a container according to theinvention and Fig. 3 shows a tube comprising such a container.

Referring to Fig. 1, reference numeral 1 designates the bulb of the tubein which an electrode system 2 is housed. At the upper end inside thetube a container 3 for the gas binder is secured, this substanceproducing a mirror 4 in the bulb after its evaporation. It is found thatadditional mirrors 5 of non-constant dimensions are produced by vapourof the gas binder emanating from the ends of the container 3. Since thedimensions of the mirror as a whole are, consequently, not constant, thecapacity of the mirror relative to the electrodes of the system 2 indifferent tubes of the same type is not the same.

In accordance with the invention the container 6 is curved as is shownin Fig. 2. The longitudinal slot 7 is provided on the concave side. At10 the cylindrical container 6 is welded to a strap 8, which is welded,as usual, to a supporting rod of the electrode system, as is shown inFigs. 1 and 3.

It is evident from Fig. 3 that the mirrors 11, produced by vapourescaping from the ends 9 of the container 6, are precipitated on thepart of the bulb 1 which is already covered with the mirror 4 by thevapour escaping from the longitudinal slot. The dimensions of the mirror4 are thus not affected by the mirrors 11, so that a constant capacityof the mirror relative to the electrodes is ensured.

Apart from the embodiment shown, other embodiments of the invention arepossible. The cylindrical containers may, for example, be bentrectangularly.

What is claimed is:

l. A vacuum tube getter holder comprising a tubular body having alongitudinal slot in the Wall thereof for storing a supply ofvaporizable gas-binding material, said tubular body having alongitudinal curvature with the slot on the inner periphery of the curveand the radius of which is such that the gas-binding material emanatesfrom the ends of the tubular member in substantially the same directionas between the ends.

2. A vacuum tube getter holder comprising a tubular body having alongitudinal slot in the wall thereof for storing a supply ofvaporizable gas-binding material, said tubular body being in the form ofa sector of a circle with the slot on the inner periphery of the circleand having a radius such that the gas-binding material emanates from theends of the tubular member in substantially the same direction asbetween the ends.

3. A vacuum tube getter holder comprising a tubular body having alongitudinal slot in the wall for storing a supply of vaporizablegas-binding material, said tubular body being in the form of a sector ofa circle with the slot on the inner periphery of the circle and theradius of which is such that the gas-binding material emanates from theends of the tubular member in substantially the same direction asbetween the ends and forms a deposit on a remotely disposed surfacewhose dimensions are determined only by the length of the longitudinalslot.

Ronci Aug. 9, 1927 Gabbrielli Jan. 22, 1957

